臭氧强化电过滤去除水中有机滤光剂的耦合增效机制与膜电极污染控制

UV filters contamination poses a threat to the water environmental and ecological security around the world, but there are few effective treatment technologies to deal with this problem. In this project, combined ozonation and electrochemical filtration with spinel ferrite modified carbon nanotube membrane electrode will be employed to treat UV filters containing wastewater. The suitable electrodes with the adsorption and catalytic effects simultaneously will be prepared and investigated. The degradation of UV filters by combined ozone-electrochemical filtration process will be systematically studied from the kinetic and mechanistic viewpoints. The degradation kinetic of the pollutants will be studied in this project on the basis of reaction rates determination. The treatment efficiency of the combined process will be evaluated, the effects of reaction parameters will be examined, and the process conditions will be optimized. Moreover, the adsorption of pollutants on the surface of electrodes and the electron transfer will be investigated. The coupling oxidation mechanism will be discussed with focus on active species analysis. Furthermore, the fouling sources and pathway of membrane electrode will be analysed, and the enhanced antifouling mechanism of membrane electrode in the combined process will be investigated. The expected results can provide scientific and theorectical basis for application of this technology in UV filters contaminated wastewater treatment.

针对水环境中有机滤光剂污染日益严重且缺乏有效处理方法的问题，结合电化学和臭氧氧化水处理技术发展现状，本项目从开发高效反应体系和深入研究耦合作用机制的关键出发，可控制备兼具吸附和催化特性的尖晶石铁氧体修饰碳纳米管膜电极，构建新型臭氧/电化学过滤耦合处理体系。通过对典型水中难降解有机滤光剂类污染物降解动力学及相关影响因素分析，考察耦合处理效能并优化反应体系；分析膜电极表面传质、吸附、电子传递、氧化还原等界面过程，探求其界面反应的调控方法；考察耦合体系中膜电极的催化氧化/还原特性，阐明羟基自由基（•OH）等活性基团的生成途径，揭示臭氧/电化学过滤的耦合作用机制；测定水处理过程中膜电极通量与电化学阻抗变化，解析膜电极污染源及其污染途径，阐明臭氧和电化学耦合抑制膜电极污染的原理，探讨对膜电极污染的调控方法。研究成果可为水中有机滤光剂污染控制提供科学依据与理论基础。

新兴有机污染物对水环境和人类健康造成潜在危害。电化学/臭氧耦合是一种新颖而高效的有机污染控制高级氧化技术，然而电极材料的研制改进和体系传质的优化仍有待解决。项目研究探明了电化学/臭氧耦合降解水中有机滤光剂类污染物的效能，采用响应面分析法阐明了臭氧投加浓度、电流密度、溶液初始pH等影响因素之间的交互作用。在电流密度20 mA/cm2，臭氧投加量为~20 mg/L时，10 min内可去除~95%的水中典型有机滤光剂类污染物奥克立林（octocrylene, OC），反应符合准一级动力学模型。在此基础上，利用锰铁氧体修饰碳纳米管研制出了新型气体扩散阴极，提高了耦合体系的传质效率和处理效能。同时，研制了铜铁氧体修饰碳纳米管粒子功能材料，在电化学/臭氧耦合体系中，粒子功能材料通过吸附-催化氧化-再生循环，显著促进了污染物和氧化基团的传质，提高了体系处理效率。进一步地，结合膜过滤的优点，构建了臭氧强化电过滤体系，实现了高效去除水中有机滤光剂类污染物并同步消减了膜污染。此外，研究揭示了羟基自由基（HO·）的生成是耦合降解污染物的主要原因，氧气在阴极还原生成过氧化氢以及臭氧在阴极得到电子生成臭氧负离子对协同生成HO·具有重要作用。铁氧体的引入，一方面可促进体系传质，另一方面可催化臭氧和过氧化氢分解生成HO·，这是体系效率提高的原因。项目的研究成果可为水中有机滤光剂去除提供技术支撑和科学依据，对水环境中有机滤光剂污染控制具有重要的理论意义和应用价值。